This invention relates generally to lubricant compositions and fuel-lubricant mixtures useful in internal combustion engines. It is particularly useful in two-cycle engines, four-cycle engines, grease lubricants, fuels (diesel and gasoline), and gears, and to methods of treating two-cycle engines, four-cycle engines, and gears to improve their cleanliness and operating efficiency.
The use of lubricants in two-cycle and four-cycle engine operation is common place. Such lubricants serve to allow facile movement between adjoining moving parts of the engine. However, the use of lubricants, as well as the fuels used to power the engine, often cause undesirable side-effects. Such side-effects include deposition of partially oxidized organic materials along pistons and other moving parts. These deposits interfere with the efficient operation of both two-cycle and four-cycle engines and gears.
Over the past several decades, the use of spark-ignited two-cycle (2-stroke) internal combustion engines has steadily increased. They are presently found in power lawn mowers and other power-operated garden equipment, power chain saws, pumps, electrical generators, marine outboard engines, snowmobiles, motorcycles and the like. The increasing use of two-cycle engines coupled with increasing severity of the conditions in which they have operated has led to an increased demand for oils to adequately lubricate such engines and which provide enhanced performance. Among the problems associated with two-cycle engines are piston ring sticking, piston scuffing, rusting, lubrication-related failure of connecting rod and main bearings and the general formation on the engine""s interior surfaces of carbon and varnish deposits. Piston ring sticking is a particularly serious problem. Ring sticking leads to failure of the sealing function of piston rings. Such sealing failure causes loss of cylinder compression which is particularly damaging in two-cycle engines because these engines depend on suction to draw the new fuel charge into the exhausted cylinder. Thus, ring sticking can lead to deterioration in engine performance and unnecessary consumption of fuel and/or lubricant. Other concerns associated with two-cycle engines include piston lubricity, scuffing and scoring.
Four cycle engines, commonly found in automobiles, have been use for over 60 years. However, their operation is still attended by problems such as the production of organic and to some extend inorganic deposits on the internal surfaces of the engine. Where these surfaces are moving parts (e.g., pistons), a severe decrease in engine operating efficiency attends such deposits.
Gears are used in industry, transportation, and many other areas. Gears transmit power and alter the direction of movement. The load on gear teeth (the load-bearing surface) is intermittent and higher than on most other bearing or loaded surfaces. The lateral sliding action of gear teeth imposes severe lubrication requirements. While gear lubricants must have superior anti-wear and extreme pressure protection they must also be non-corrosive to xe2x80x9cyellow metalxe2x80x9d (copper alloy) components. Gear lubricants, particularly ones used in mining, milling, and similar operations need to be composed of high viscosity index oils and extreme pressure/anti-wear agents.
Grease lubrication of bearings, gears, and other components is used when seals or other devices can not be used to prevent migration of the lubricant away from lubricated surfaces. Grease consists of thickeners, typically 6 to 10 percent by weight of the mixture, lubricating oil, and additives to enhance the performance of the grease. The thickener in grease acts as a xe2x80x9cspongexe2x80x9d to keep the oil and additives on the bearing, gear, or other component being lubricated. The additives used in grease blending are similar to the ones used in the production of gear, engine oil, and other petroleum based lubricants.
The lubrication of fuel system components such as diesel pumps, diesel injectors, gasoline engine valves, the upper cylinder, and ring area of four cycle and two cycle engines has become an important area of research as fuel composition changes to meet new environmental regulations. Upper cylinder lubricants act to lubricate and clean the ring and upper cylinder area of spark and compression ignition engines. This action can benefit fuel economy, emissions, as well as ring and cylinder wear. The introduction of low sulfur diesel fuels has increased wear in pumps and diesel fuel injectors. Lubricants that will operate successfully at high temperatures and not contribute to damage of emission control devices are difficult to develop.
All of the aforementioned problems associated with two-cycle and four-cycle engines must be adequately addressed. Improved performance is continually being sought. The unique problems and techniques associated with the lubrication of two-cycle and four-cycle engines has led researches to develop a wide variety of products. However, further improvements in terms of combustion efficiency, lubrication efficiency and the like are still needed. The present invention fulfills these needs and provides further advantages in the context of in engine lubrication.
In brief, the present invention is directed to lubricant and anti-wear compositions for two-cycle and four-cycle engines. Suitable compositions for two-cycle engines comprise a copolymer of an alpha olefin and diester selected from a dialkyl fumarate and a dialkyl maleate, an aliphatic diester having exactly two ester groups and about 20-40 carbon atoms, preferably in the presence of an octane booster, such as methylcyclopentadienyl manganese tricarbonyl.
Suitable anti-wear compositions for four-cycle engines comprise a copolymer of an alpha olefin and diester selected from a dialkyl fumarate and a dialkyl maleate, a molybdenum or bismuth compound, an anti-corrosion additive such as dimercapto 1,3,4 thiadiazole and a extreme pressure additive such as sulfur-phosphorous EP or chlorinated paraffin. A fullerene compound (optionally dissolved in mineral oil) is a preferred optional ingredient for the anti-wear composition.
Another suitable gear lubricant composition is made with a copolymer of an alpha olefin and diester selected from a dialkyl fumarate and a dialkyl maleate, a molybdenum or bismuth compound, an anti-corrosion additive such as dimercapto 1.3.4 thiadiazole. A fullerene compound (optionally dissolved in mineral oil) is a preferred optional ingredient for the anti-wear composition. This blend may also be used as an anti-wear and extreme pressure additive in grease and fuels.
Another suitable composition for four-cycle engines is termed herein a synthetic lubricant composition (SLC) and comprises one or both of a copolymer of an alpha olefin and diester selected from a dialkyl fumarate and a dialkyl maleate, and an aliphatic diester having exactly two ester groups and about 20-40 carbon atoms. The SLC further comprises a molybdenum or bismuth compound, an anti-corrosion additive such as dimercapto 1,3,4 thiadiazole, and extreme pressure additive such as sulfur-phosphorous EP or chlorinated paraffin (optionally in an oil (e.g., vegetable oil) base), and fullerene (optionally in an oil (e.g., naphthalenic oil) base).
In another aspect, the invention is directed to operation of two-cycle and four-cycle engines using the compositions of the invention, as well as gear oil and grease lubricants.
These and other aspects of this invention will become apparent upon reference to the following detailed description.
As briefly explained above, the invention is directed to compositions that may be added to internal combustion engines, particularly two-cycle and four-cycle engines, in order to improve the performance thereof. In addition, the invention is directed to methods of operating internal combustion engines under conditions of high efficiency and cleanliness of operation. The various compositions of the invention will now be described, followed by a more detailed description of their required and optional ingredients.
The invention provides for an anti-wear additive concentrate suitable for a four-cycle engine. This concentrate contains ester copolymer, one or more molybdenum or bismuth compounds, dimercapto 1,3,4 thiadiazole compound and at least one of sulfur-phosphorous EP and chlorinated paraffin. A preferred optional ingredient for the anti-wear additive concentrate is a fullerene-rich oil, and a further preferred optional ingredient is a mineral oil.
The anti-wear additive concentrate contains, on a volume percent basis based on the total volume of the concentrate, the following amounts of the various required and optional components. Ester copolymer: 1-20, preferably 2-10.
Molybdenum or bismuth compound: 10-50, preferably 20-40. Dimercapto 1,3,4 thiadiazole compound: 1-10, preferably 2-8. Sulfur-phosphorous EP and/or chlorinated paraffin: 10-50, preferably 15-45. Mineral oil: 10-40, preferably 15-30. Fullerene: 0.1 to 2.5, preferably 0.5 to 2.
The anti-wear additive would typically be used by manufacturers of motor oil and would constitute a portion of the motor oil. The anti-wear additive might be blended with a base lubricant or oil to provide a hydraulic oil, gear oil or grease. Methods of blending and components suitable for motor oil, hydraulic oil, gear oil, grease and the like are well known to those of skill in the art.
The invention also provides for a SLC engine treatment suitable for a four-cycle engine, where SLC stands for synthetic lubricant concentrate. The SLC engine treatment contains at least one of ester copolymer and diester, as well as a molybdenum or bismuth compound, dimercapto, 1,3,4 thiadiazole, at least one of sulfur-phosphorous EP (optionally in combination with vegetable oil base) and chlorinated paraffin, and also contains fullerene rich oil. A preferred optional ingredient for the SLC engine treatment is mineral oil and/or a motor oil additive package.
The SLC engine treatment contains, on a volume percent basis based on the total volume of the engine treatment, the following amounts of the various required and optional components: ester copolymer and/or diester: 1-15, preferably 2-10. Molybdenum or bismuth compound: 1-50, preferably 20-40. Dimercapto, 1,3,4 thiadiazole compound: 1-10, preferably 2-8.
Sulfur-phosphorous EP (optionally with vegetable oil base) and/or chlorinated paraffin: 1-40, preferably 10-35. Mineral oil: 10-40, preferably 15-30. Fullerene rich oil: 1-5, preferably 2-4. Motor oil additive package: 1-30, preferably 10-20.
The SLC may be added directly to a car or other motor vehicle engine, along with the oil which is typically added to the engine. Preferably the engine is a four-cycle engine.
In another aspect, the invention also provides for a two-cycle engine treatment composition. This composition contains at least ester copolymer, diester and methylcyclopentadienyl manganese tricarbonyl. Preferred optional ingredients for the two-cycle engine treatment composition contains base oil and liquid hydrocarbon. The two-cycle engine treatment composition contains, on a volume percent basis based on the total volume of the composition, the following amounts of the various required and optional components: ester copolymer: 1-20, preferably 5-15. Diester oil: 1-40, preferably 15-30. Methylcyclopentadienyl manganese tricarbonyl: 0.1-5, preferably 0.5-2, more preferably 0.5-1. Base oil: 20-70, preferably 40-50. Liquid hydrocarbon: 5-50, preferably 20-35.
The ester copolymer and diester together afford cleanup and emission (smoke) reduction benefits. A volume ratio of ester copolymer: diester of about 1:1-1:4, preferably about 1:2 is preferred. It is also preferred that about 20-50, and more preferably about 25-40 volume percent of the two-cycle engine treatment composition consists of the blend of ester copolymer and diester.
A preferred composition for treatment of a two-cycle engine contains 8-15 volume percent of ester copolymer, preferably KETJENLUBE 1300; 10-25 volume percent of diester, preferably VISTONE A-30; 25-60 volume percent polyisobutylene, 10-30 volume percent of an aliphatic solvent such as kerosene; 1-5 volume percent of a detergent, preferably a calcium salt, and 0.5-2 volume percent of a combustion enhancer, preferably a manganese compound such as methylcyclopentadienyl manganese tricarbonyl. The two-cycle engine treatment composition may be added to the oil inlet of a two-cycle oil-injection motor, or may be blended with gasoline or other fuel (1 volume part two-cycle engine treatment to 10-100 volume parts fuel, preferably to about 50 parts fuel) and the blend used to power a two-cycle engine.
The various components of the engine treatment compositions described above will discussed in greater detail.
One component of the engine treatments is an ester copolymer (also referred to herein as xe2x80x9cthe copolymerxe2x80x9d), which is the copolymerization product of an alpha-olefin and a dialkyl fumarate or dialkyl maleate. The copolymerization is preferably a random copolymerization. The alpha-olefin is preferably a C6-18, more preferably a C8-16, still more preferably a C10-14 and yet still more preferably a C12 alpha-olefin. The term alpha-olefin refers to a straight chain of the indicated number of carbon atoms, where a double bond is present between two end carbons, i.e., C6 alpha-olefin has the formula C4xe2x80x94CHxe2x95x90CH2 while the C12 alpha-olefin has the formula C10xe2x80x94CHxe2x95x90CH2.
As used herein, the designation Cx or Cx-y means a hydrocarbon containing X carbon atoms or X to Y carbon atoms, respectively, including straight chain or branched, saturated or unsaturated, cyclic or acyclic hydrocarbons.
The alkyl group of the dialkyl fumarate or maleate is a C1-10 alkyl group, preferably a C2-6 alkyl group and more preferably a C4 alkyl group. Both of the fumarate and maleate contains two alkyl group, and these group may be the same or different in terms of carbon number. While either fumarate or maleate diesters are suited for the ester copolymer, fumarate diester is preferred.
The ester copolymer has an average molecular weight (Mw) of about 600 to about 7,000. The viscosity may be as high as about 700 mm2/s at 100xc2x0 C., is preferably about 100-500 mm2/s, and more preferably is about 200-300 mm2/s.
Such ester copolymers may be prepared by free-radical polymerization techniques, as are known in the art. Alternatively, these ester copolymers may be obtained commercially. For example, a copolymer between C12 alpha-olefin and dibutylfumarate is available under the trademark KETJENLUBE from Akzo Chemicals (Dobbs Ferry, N.Y.).
The ester copolymer serves to provide lubricity, anti-wear, dispersancy, extreme pressure and deposit control (engine cleanliness) properties to the inventive compositions. The ester copolymer may also be referred to as an anti-scuff agent.
Another component is a diester which, as its name implies, is a molecule formed from two ester groups. The diester is also referred to herein as xe2x80x9cthe diester oil,xe2x80x9d and has the formula C2-24OC(xe2x95x90O)xe2x80x94C2-10xe2x80x94C(xe2x95x90O)Oxe2x80x94C2-24, preferably has the formula C6-20OC(xe2x95x90O)xe2x80x94C2-8xe2x80x94C(xe2x95x90O)Oxe2x80x94C6-20, more preferably has the formula C10-16OC(xe2x80x94O)xe2x80x94C2-6xe2x80x94C(xe2x80x94O)Oxe2x80x94C10-16, and still more preferably has the formula C13OC(xe2x80x94O)C4C(xe2x80x94O)O C13. Thus the diester is of fairly high molecular weight, preferably having at least about 20, more preferably at least about 30 carbon atoms, all of which are saturated and aliphatic.
Such diester oils may be prepared by condensation reaction between a dicarboxylic acid of the formula HOOCxe2x80x94C2-10xe2x80x94COOH and a monohydric alcohol of the formula C2-24xe2x80x94OH. Thus, the dicarboxylic acid and monohydric alcohol (or mixtures thereof) may be combined and heated until esterification is achieved, typically about 100-250xc2x0 C. Such esterification reactions are well known in the art, and the starting materials (i.e., the dicarboxylic acid and the monohydric alcohol) are commercially available from, e.g., Aldrich Chemical Company (Milwaukee, Wis.).
The diester oils may also be purchased commercially. For example, ditridecyl adipate is available under the trademark VISTONE A-30 from Exxon Chemical (Houston, Tex.).
The diester oil serves to provide lubricity, anti-wear and deposit control properties to the inventive compositions. The diester oil may also be referred to as a synthetic base oil.
A further component is methylcyclopentadienyl manganese tricarbonyl (MCMT). MCMT is available commercially under the trademark ETHYL MMT from Ethyl Corporation (Richmond, Va.). MCMT serves to impart emission control to the inventive composition by aiding in the combustion of the oil-gasoline mixture, i.e., it serves as a combustion enhancer. MCMT serves to impart deposit control to the inventive composition by promoting complete combustion of the mixture, and can further assist in the removal of existing carbon deposits from exhaust ports and piston crowns. MCMT is typically an optional component in the inventive compositions, and other chemicals which can provide the combustion enhancement afforded by MCMT may be used in addition to, or in place of MCMT.
A further component is a base oil. Base oils typically contain detergent, solvent and hydrocarbon polymer, e.g., polyisobutylene. Such a mixture which contains polyisobutylene is available commercially under the trademark PARATEMPS 102 from Exxon Chemicals (Houston, Tex.).
Another component is a motor oil additive package. Such packages are commercially available, and serve to provide wear and deposit control to the inventive composition. Lubrizol (Wickliffe, Ohio) sells a motor oil additive package under their trademark LUBRIZOL 4994A, which may be used in the inventive composition.
Another component is a liquid hydrocarbon. When present in the inventive composition, the liquid hydrocarbon acts to lower the viscosity of the inventive composition and to lower its temperature pour. It also eases mixing of the inventive composition into gasoline. A suitable liquid hydrocarbon is kerosene. However, other liquid hydrocarbons of similar composition, e.g., jet fuel may be employed in the invention. Such liquid hydrocarbons are widely available from many commercial suppliers.
Another component is an Olefin Co-Polymer. The polymer compounds (Olefin Co-Polymers) are used as thickening agents. As used herein, a thickening agent is any substance which increases the viscosity of the composition. Such thickening agents include Nordel 4549, Lubrizol 7060A, Lubrizol 7065 and Paratone 715. The purpose of these thickeners is to provide rust and corrosion protection, keep the inventive composition on open gear surfaces (when used as on an open gear lube), and to add body or thicken lubricating oil that the inventive composition is mixed with.
A further component is an organo-molybdenum compound which contains a single molybdenum atom. The molybdenum atom is preferably complexed by a sulfur-containing ligand. Suitable ligands include thiophosphate and dithiocarbamate. Thus, molybdenum thiophosphate and molybdenum dithiocarbamate are suitable organo-molybdenum compounds for the inventive composition. These materials are commercially available. For example, molybdenum thiophosphate is available under the trademark MOLYVAN L from while molybdenum dithiocarbamate is available under the trademark MOLYVAN 822 from R. T. Vanderbilt Corporation (Norwalk, Conn.). Another suitable molybdenum compound is 2-ethylhexyl molybdenum dithiophosphate, which is commercially available as ADDITIN RC 3580 from Rhein Chemie (Trenton, N.J.).
Another component is a bismuth complex. An exemplary bismuth complex is bismuth naphthenate, which is available commercially as LIOVAC 3016 and is made by Miracema-Nuodex Industries, Ltd., Campinas-SP, Brazil.
The organo-molybdenum and/or the bismuth complex serves to provide lubricity, anti-wear and anti-oxidant properties to the inventive composition.
A further component is dimercapto, 1,3,4 thiadiazole. This material is commercially available under the trademark AMOCO 158 from The Ethyl Corporation (Orange, Calif.), VANLUBE 871 from R. T. Vanderbilt Corporation (Norwalk, Conn.) and ADDITIN TC 8210 from Rhein Chemie (Trenton, N.J.). The dimercapto, 1,3,4 thiadizole serves to impart anti-wear, extreme pressure and anti-corrosion performance properties to the inventive composition.
Another component is sulfur-phosphorous EP and/or chlorinated paraffin. Either of these materials, or the combination thereof, serves to provide extreme pressure and anti-wear properties to the inventive composition. Sulfur-phosphorous EP is also known as sulfur phosphorous gear oil, and is commercially available under the trademark ANGLAMOL 6043 from Lubrizol Corp. (Wickliffe, Ohio) while chlorinated paraffin is commercially under the trademark PAROIL 50L50 from Dover Chemical Corporation (Dover, Ohio).
A further component is a fullerene rich oil. Such an oil may be prepared by dissolving fullerene powder in a naphthenic base oil. In order to prepare the Fullerene Rich Oil, Fullerene Rich Soot or Pure Fullerene Compounds may be purchased from Texas Fullerenes Company (Houston, Tex.), or Fluka. The Fullerene Rich Soot is added to Benzene. The soot does not dissolve, however the Fullerenes will. Decant Benzene Fullerene mixture, and dry to obtain xe2x80x9cpurexe2x80x9d Fullerene compound. Add this compound to Naphthetic 60 Second Oil or equivalent. 60 Second Oil can be purchased from Shell (Portland, Oreg.) or Witco (Los Angeles, Calif.). Typically 2 grams of Fullerene material is added to 2 gallons of 60 Second Oil. However, as little as about 0.2 grams and as much as about 20 grams of the Fullerene material could be added to the 2 gallons of 60 Second Oil.
A further component is mineral oil. A suitable mineral oil has about 200 to about 600 SUS at 100xc2x0 F., and preferably has 450 SUS at 100xc2x0 F. Such mineral oil is commercially available. For example, mineral oil with 450 SUS at 100xc2x0 F. is available under the trademark HVI 450 NEUTRAL from Mohawk Lubricants (North Vancouver B.C., Canada). Similar products are available from Chevron, U.S.A. (Richmond, Calif.) and Exxon U.S.A. (Houston, Tex.).
It is sometimes useful to incorporate to any of the afore-described anti-wear concentrate, SLC engine treatment or two-cycle engine treatment, on an optional, as needed basis, other known additives which include, but are not limited to, dispersants and detergents of the ash-producing or ashless type, antioxidants, anti-wear agents, extreme pressure agents, emulsifiers, demulsifiers, foam inhibitors, friction modifiers, anti-rust agents, corrosion inhibitors, viscosity improvers, pour point depressants, dyes, lubricity agents, and solvents to improve handleability which may include alkyl and/or aryl hydrocarbons. These optional additives may be present in various amounts depending on the intended application for the final product or may be excluded therefrom.
The ash-containing detergents are the well-known neutral or basic Newtonian or non-Newtonian, basic salts of alkali, alkaline earth and transition metals with one or more hydrocarbyl sulfonic acid, carboxylic acid, phosphoric acid, mono- and/or dithio phosphoric acid, phenol or sulfur coupled phenol, and phosphinic and thiophosphinic acid. Commonly used metals are sodium, potassium, calcium, magnesium, lithium, copper and the like. Sodium and calcium are most commonly used.
Neutral salts contain substantially equivalent amounts of metal and acid. As used herein, the expression basic salts refers to those compositions containing an excess amount of metal over that normally required to neutralize the acid substrate. Such basic compounds are frequently referred to as overbased, superbased, etc.
Dispersants include, but are not limited to, hydrocarbon substituted succinimides, succinamides, carboxylic esters, Mannich dispersants and mixtures thereof as well as materials functioning both as dispersants and viscosity improvers. The dispersants include nitrogen-containing carboxylic dispersants, ester dispersants, Mannich dispersants or mixtures thereof. Nitrogen-containing carboxylic dispersants are prepared by reacting a hydrocarbyl carboxylic acylating agent (usually a hydrocarbyl substituted succinic anhydride) with an amine (usually a polyamine). Ester dispersants are prepared by reacting a polyhydroxy compound with a hydrocarbyl carboxylic acylating agent. The ester dispersant may be further treated with an amine. Mannich dispersants are prepared by reacting a hydroxy aromatic compound with an amine and aldehyde. The dispersants listed above may be post-treated with reagents such as urea, thiourea, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon substituted succinic anhydride, nitrites, epoxides, boron compounds, phosphorus compounds and the like. These dispersants are generally referred to as ashless dispersants even though they may contain elements such as boron or phosphorus which, on decomposition, will leave a non-metallic residue.
Extreme pressure agents and corrosion- and oxidation-inhibiting agents include chlorinated compounds, sulfurized compounds, phosphorus containing compounds including, but not limited to, phosphosulfurized hydrocarbons and phosphorus esters, metal containing compounds and boron containing compounds.
Chlorinated compounds are exemplified by chlorinated aliphatic hydrocarbons such as chlorinated wax.
Examples of sulfurized compounds are organic sulfides and polysulfides such as benzyl disulfide, bis(-chlorobenzyl)disulfide, dibutyl tetrasulfide, sulfurized methyl ester of oleic acid, sulfurized alkylphenol, sulfurized dipentene, and sulfurized terpene.
Phosphosulfurized hydrocarbons include the reaction product of a phosphorus sulfide with turpentine or methyl oleate.
Phosphorus esters include dihydrocarbon and trihydrocarbon phosphites, phosphates and metal and amine salts thereof.
Phosphites may be represented by the following formulae: 
wherein each R5 is independently hydrogen or a hydrocarbon based group, provided at least one R5 is a hydrocarbon based group.
Phosphates esters include mono-, di- and trihydrocarbon-based phosphates of the general formula
(R5O)3PO. 
Examples include mono-, di- and trialkyl; mono-, di- and triaryl and mixed alkyl and aryl phosphates.
Metal containing compounds include metal thiocarbamates, such as zinc dioctyldithiocarbamate, and barium heptylphenyl dithiocarbamate, and molybdenum compounds.
Boron containing compounds include borate esters and boron-nitrogen containing compounds prepared, for example, by the reaction of boric acid with a primary or secondary alkyl amine.
Viscosity improvers include, but are not limited to, polyisobutenes, polymethacrylate acid esters, polyacrylate acid esters, diene polymers, polyalkyl stryrenes, alkenyl aryl conjugated diene copolymers, polyolefins and multifunctional viscosity improvers.
Pour point depressants are a particularly useful type of additive often included in the lubricating oils described herein. See, for example, page 8 of xe2x80x9cLubricant Additivesxe2x80x9d by C. V. Smalheer and R. Kennedy Smith (Lesius-Hiles Company Publishers, Cleveland, Ohio, 1967).
Lubricity agents include synthetic polymers (e.g., polyisobutene having a number of average molecular weight in the range of about 750 to about 15,000, as measured by vapor phase osmometry or gel permeation chromatography), polyolether (e.g., poly(oxyethylene-oxypropylene ethers) and ester oils. Natural oil fractions such as bright stocks (the relatively viscous products formed during conventional lubricating oil manufacture from petroleum) can also be used for this purpose. They are usually present, when used in two-cycle oils, in amounts of about 3% to about 20% by volume of the total composition.
Diluents include such materials as petroleum naphthas boiling in the range of 30xc2x0 to about 90xc2x0 C. (e.g., Stoddard Solvent). When used, they are typically present in amounts ranging from about 5% to about 25% by volume.
Anti-foam agents used to reduce or prevent the formation of stable foam include silicones or organic polymers. Examples of these and additional anti-foam compositions are described in xe2x80x9cFoam Control Agents,xe2x80x9d by Henry T. Kerner (Noyes Data Corporation, 1976), pages 125-162.
These and other additives are described in greater detail in U.S. Pat. No. 4,582,618 (column 14, lines 52 through column 17, line 16, inclusive), herein incorporated by reference for its disclosure of other additives that may be used in the compositions of the present invention.
The components may be blended together in any suitable manner and then admixed, for example with a diluent to form a concentrate as discussed below, or with a lubricating oil, as discussed below. Alternatively, components can be admixed separately with such diluent or lubricating oil. The blending technique for mixing the components is not critical and can be effected using any standard technique, depending upon the specific nature of the materials employed. In general, blending can be accomplished at room temperature; however, blending can be facilitated by heating the components.
As previously indicated, the two-cycle engine treatment compositions of the present invention are useful as additives for lubricants for two-cycle engines. They can be employed in a variety of lubricant basestocks comprising diverse oils of lubricating viscosity, including natural and synthetic lubricating oils and mixtures thereof.
Natural oils include animal oils, vegetable oils, mineral lubricating oils, solvent or acid treated mineral oils, and oils derived from coal or shale. Synthetic lubricating oils include hydrocarbon oils, halo-substituted hydrocarbon oils, alkylene oxide polymers, esters of carboxylic acids and polyols, esters of polycarboxylic acids and alcohols, esters of phosphorus-containing acids, polymeric tetrhydrofurans, silicon-based oils and mixtures thereof.
Specific examples of oils of lubricating viscosity are described in U.S. Pat. No. 4,326,972 and European Patent Publication 107,282, both herein incorporated by reference for their disclosures relating to lubricating oils. A basic, brief description of lubricant base oils appears in an article by D. V. Brock, xe2x80x9cLubricant Base Oils,xe2x80x9d Lubrication Engineering, volume 43, pages 184-185, March, 1987. This article is herein incorporated by reference for its disclosures relating to lubricating oils. A description of oils of lubricating viscosity occurs in U.S. Pat. No. 4,582,618 (column 2, line 37 through column 3, line 63, inclusive), herein incorporated by reference for its disclosure to oils of lubricating viscosity.
As is well known to those skilled in the art, two-cycle engine lubricating oils are often added directly to the fuel to form a mixture of a lubricant and fuel which is then introduced into the engine cylinder. Such lubricant-fuel mixtures are within the scope of this invention. Such lubricant-fuel mixtures generally contain a major amount of fuel and a minor amount of lubricant, more often at least about 10, preferably about 15, more preferably about 20 up to about 100, more preferably up to about 50 parts of fuel per 1 part of lubricant.
The fuels used in two-cycle engines are well known to those skilled in the art and usually contain a major portion of a normally liquid fuel such as hydrocarbonaceous petroleum distillate fuel (e.g., motor gasoline as defined by ASTM Specification D-439-73). Such fuels can also contain non-hydrocarbonaceous materials such as alcohols, ether, organo-nitro compounds and the like (e.g., methanol, ethanol, diethyl ether, methyl ethyl ether, nitromethane) are also within the scope of this invention as are liquid fuels derived from vegetable or mineral sources such as corn, alfalfa, shale and coal. Mixtures of fuels, such as mixtures of gasoline and alcohol, for example, methanol or ethanol are among the useful fuels.
Examples of fuel mixtures are combinations of gasoline and ethanol, diesel fuel and ether, gasoline and nitromethane, etc. Particularly preferred is gasoline, that is, a mixture of hydrocarbons having an ASTM boiling point of 60xc2x0 C. at the 10% distillation point to about 205xc2x0 C. at the 90% distillation point.
Natural gas is also useful as a fuel for two-cycle engines.
Two-cycle fuels also contain other additives which are well known to those of skill in the art. These may include ethers, such as ethyl-t-butyl ether, methyl-t-butyl ether and the like, alcohols such as ethanol and methanol, lead scavengers such as halo-alkanes (e.g., ethylene dichloride and ethylene dibromide), dyes, certain improvers, antioxidants such as 2,6 di-tertiary-butyl-4-methylphenol, rust inhibitors, such as alkylated succinic acids and anhydrides, bacteriostatic agents, gum inhibitors, metal deactivators, demulsifiers, upper cylinder lubricants, anti-icing agents and the like. The invention is useful with lead-free as well as lead-containing fuels.